Electromagnetic-horn apparatus



July N, 1951 W. L. BARROW ELECTROMAGNETIC-HORN APPARATUS Filed Feb. 19. 1946 OSCILLATOR IN V EN TOR.

WILMER L. BARROW .ATTORNEY Patented July 1' 7, 1951 Wilmer Lanier Barrow, Manhasset, N. Y., as-

signor, by mesne assignments, to The Sperry Corporation, Great Neck, N. Y., a corporation of Delaware Application February 19, 1-946, Serial No. 648,769 5 Claims. (01. 250-3353) The present invention relates to electromagnetic-horn apparatus. The present application is a continuation-in-part of application, Serial No. 155,489, filed July 24, 1937, now Patent No. 2,425,716, granted August 19, 1947.

An object of the present invention is to provide a new and improved multi-unit electromagnetic horn.

Another object is to provide new and improved 'ele'ctromagneticehorn apparatus suitable for radiating in a plurality of directions.

Other and further objects will be explained hereinafter and will be particularly pointed out in the appended claims.

The invention will now be more fully described in connection with the accompanying drawings, the single figure of which is a diagrammatic View of circuits and apparatus showing, in perspective, an electromagnetic horn embodyin the present invention connected to suitable sending equipment.

In the drawing, there is shown, for illustrative purposes, a transmitting system comprising an ultra-high-frequency oscillator 2, provided with a modulator 3, which may be modulated in any desired way, as by means of a microphone 4. The modulated output may be fed 'to a radio-frequency amplifier 6 that may be coupled to a circuit 8 having two-wire output-conductor connecting leads l0 and I2. One of the leads, as the lead 10, is shown connected to one end of the outer tubular conducting body portion 35 of a coaxial-line system. The other lead, as the lead 12, is shown connected to one end of the inner conducting exciting or absorbing stem or rod [4 of the coaxial-line system, disposed approxi- [I'nately axially of the tubular body portion 35. The leads Ill and i2 may, however, be connected to other types of terminal device, including conventional parallel-line, hollow-pipe wave-guide transmission-line and other systems.

The other end of the tubularbody portion 35 of the coaxial-line system is shown connected to a hollow-pipe wave-guide 78. The other'end of the stem or rod I4 is shown extending into the wave-guide 78 substantially at right angles ffto the axis of the wave-guide 78. Three hollow- '=pipe wave-guide sections 74, 75, and 76 are shown joined together and to the hollow-pipe section 78 at a branch fitting 77. Three electromagnetic flaring horns 7|, 72, and 73, arranged in a space array, are respectively connected at their small or throat ends to the three sections of hollowfpip'e transmission lines 74, 75, and 76. The horns "may be conical, pyramidahsectoral, or of any "iither desired shape, depending upon the appucation. They may or may not be disposed in a single plane, shown horizontal. They need not be equally spaced. The lengths of the wave guide sections 74, 75, and 76 are adjusted so as to give the desired relative phases and amplitudes of the electromagnetic waves in the individual wave-guide sections 74, 75, and 76 and, therefore, at the mouth of the respective horns 7|, 72, and 73, in order to provide, in transmission, a composite radiation or absorption pattern having desired directive or other characteristics. The composite radiation or absorption pattern will be a function of the radiation or absorption patterns of the individual horns and of the characteristics of the respective waveguide sections 74, 75, and 76. One of the lobes of the pattern of one horn, for example, may be caused to reinforce a lobe of the pattern of another horn, and other lobes may be partly or wholly suppressed.

In the illustrated embodiment of the invention, the pattern will be such as to produce a beam of relatively wide angle and uniform intensity.

Other combinations and arrangements may be used to provide other shapes of radiation pattern. If the horns 7!, 72, and 73 are directed parallel, for example, added gain may be obtained over what is attainable with the use of only a single horn. It is possible also to operate the horns at different carrier frequencies, and also with different modulations of those carrier frequencies, so as to operate with different signals.

v The wave-guide sections 74, 75, and 76 and the horns 74, 75, 76 respectively connected therewith are shown disposed in a horizontal plane, but this is not essential, except insofar as a horizontal plane pattern may be desired. 'By disposing the elements in different planes, a nonplanar pattern may be obtained.

The large end of each horn is electromagnetically open to space to permit the horn to receive electromagnetic waves from space or to radiate electromagnetic waves out into space at the large end. The transverse dimension -of the small end or throat of each horn is substanhollow pipe of the same cross-sectional shape as that of the small end of the horn. The principal axis of each horn extends between the small "and the large ends of the horn substantially at "right angles to the rod l4.

Sending or receiving apparatus may beco'nnected to the two-wire connecting leads l and I2. As before stated, Fig. 1 illustrates a sending system. The corresponding connections for receiving will be understood by persons skilled in the art without further illustration.

In transmission, owing to the disposition of the exciting rod l4, transversely polarized modulated ultra-high-frequency electromagnetic energy may be taken by the conductors l0 and I2 from the sending apparatus and delivered to the concentric line 35, M, by which it will be delivered to the wave guide 18 and, through the wave-guide sections l4, l5, and 76, to the throats of the respective horns l I, 12, and I3. The modulated electromagnetic energy will then be propagated through the interiors of the horns to their large ends or mouths. Upon arrival at the mouths of the horns, the electomagnetic waves become readily disattached from the horn surfaces, continuing thereafter to travel forward out into free space, as ordinary modulated radio waves. The direction of progression of the waves in free space is predetermined by the design of the horn. The horns thus constitute directive electromagnetic radiators.

Similar but reverse action will take place during reception of such waves. Transversely polarized modulated electromagnetic waves will be received at the large'ends or mouths of the horns and, after traveling through the interior of the horns, to the throats thereof, and through the wave-guide sections l4, l5, 16, to the waveguide 18, will be absorbed by the coaxial line 35, M, by which they will be conducted to a receiving system (not shown), where the signals comprising the intelligence will be demodulated. These signals may be combined at the receiving station in any well known manner after demodulation, correspondin to their combination at the transmitting station during modulation.

The electromagnetic horns ll, 12, and 13 are each provided with a guiding surface or guiding walls that connect the small ends or throats thereof with their large ends or mouths. Each horn thus operates to guide the electromagnetic waves traveling through the dielectric within it tangentially along its conducting guiding surface in the longitudinal direction, more or less parallel to its principal axis, smoothly, continufously, and without interruption. In reception,

mouth for directive transmission, and the field configuration of the waves is reasonably maintained during their outward progression. The

waves become thus slidingly attached to the conducting guiding horn surface, and they remain so continuously attached throughout their sliding, thus guided, movement along this horn surface, from the small end or throat of the horn 'until they reach the mouth of the horn. A similar operation take place durin reception.

The waves travel with a phase velocity substantially different from that of light in the medium of the horn. Near the small end of the born, the phase velocity may be very much 4 greater than the velocity of light. The phase velocity decreases as the large end or mouth of the horn is reached until, just at or beyond the mouth of the horn, the phase velocity may be exactly the same as that of light.

A plurality of open-ended horns may thus be disposed in a space array, with their large ends or mouths connected to free space and their small ends or throats connected to common wave-guide or other apparatus 18, for purposes of either radiating radio waves into, or absorbing them from, space. If the multi-unit horn is used for the transmission or the reception of ultra-high-frequency waves of wave lengths below ten meters, the dimensions of the apparatus may be kept reasonably small.

Multi-unit horns of the above-described character, operated at ultra-high frequencies, have numerous applications. They may be used, for example, for aerial and marine navigation, confined or secret point-to-point communication, direction, distance, obstacle and height indication, and broad-band point-to-point transmission. They are characterized by flexibility of operation, electrical steerability, and relatively small length compared to the length of single horns of equivalent effectiveness.

Modifications will occur to those skilled in the art, and all such are considered to be within the scope and spirit of the invention, as defined in the appended claims.

What is claimed is:

1. A transmitting or receiving system for radio waves comprising a plurality of electromagnetic horns disposed in a space array, separate wave guides of unequal length connecting each of said horns to common apparatus, and means for exciting electromagnetic waves for transmission from the common apparatus to the horns or for absorbing electromagnetic waves received by the common apparatus from the horns, whereby a desired asymmetrical radiation pattern is obtained.

2. A transmitting or receiving system for radio waves comprising a plurality of electromagnetic horns disposed in a space array, means for exciting electromagnetic waves for transmission from common apparatus to the horns or for absorbing electromagnetic waves received by the common apparatus from the horns, and separate wave guides of unequal length for connecting each of said horns to common apparatus for choosing the relative phases of amplitudes of the electromagnetic waves, whereby a desired asymmetrical radiation pattern is obtained.

3. A transmitting or receiving system for radio waves comprising a plurality of electromagnetic horns disposed in a space array, each horn having a large end and a small end and a principal axis extending between the ends, unequal length wave-guide means for connecting the small ends of the horns to common apparatus, and means comprising an exciting or absorbing rod disposed substantially at right angles to the principal axes of the horns for exciting transversely polarized electromagnetic waves for transmission from'the common apparatus to the horns or for absorbing transversely polarized electromagnetic waves received by the common apparatus from the horns.

4. A transmitting or receiving system for radio waves comprising a wave-guide, a plurality of unequal length wave-guide sections connected with the wave-guide, an electromagnetic horn connected with each wave-guide section, and

means for transmitting electromagnetic waves from the wave-guide through the wave-guide sections to the horns respectively connected with the wave-guide sections or for absorbing electromagnetic waves received by the wave-guide sections from the horns respectively connected with the wave-guide sections and for transmitting the electromagnetic waves through the respective wave-guide sections to the wave-guide.

5. A transmitting or receiving system for radio waves comprising a wave-guide, a plurality of unequal length wave-guide sections connected with the wave-guide, an electromagnetic horn connected with each wave-guide section, and means for transmitting electromagnetic waves from the wave-guide through the wave-guide sections to the horns respectively connected with the wave-guide sections or for absorbing electromagnetic waves received by the wave-guide sections from the horns respectively connected with the WILMER LANIER BARROW.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,992,268 Wente Feb. 26, 1935 2,206,683 Wolff July 2, 1940 2,206,923 Southworth July 9, 1940 2,297,202

Dallenbach et al. Sept. 29, 1942 Certificate of Correction Patent No. 2,560,541 July 17, 1951 WILMER LANIER BARROW It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 4, line 53, for phases of read phases or;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 23rd day of October, A. D. 1951.

THOMAS F. MURPHY,

Assistant Gammissz'oner of Patents. 

